1、BRITISH STANDARD BS4639:1987 Specification for Brakes and braking systems for towed agricultural vehicles UDC631.373:629.114.3-592BS4639:1987 This British Standard, having been prepared under the directionof the Agricultural Machinery and Implements Standards Committee, was published under the autho
2、rity ofthe Board of BSI and comes intoeffect on 31 March1987 BSI08-1999 First published October1970 First revision March1987 The following BSI references relate to the work on this standard: Committee reference AGE/17 Draft for comment82/77040 DC ISBN 0 580 13914 X Committees responsible for this Br
3、itish Standard The preparation of this British Standard was entrusted by the Agricultural Machinery and Implements Standards Committee(AGE/-) to Technical Committee AGE/17 upon which the following bodies were represented: Agricultural Engineers Association British Agricultural and Garden Machinery A
4、ssociation Ltd. Department of Transport Flour Milling and Baking Research Association Health and Safety Executive Institute of Brewing Ministry of Agriculture, Fisheries and Food National Farmers Union National Institute of Agricultural Engineering National Union of Agricultural and Allied Workers U
5、nited Kingdom Agricultural Supply Trade Association Ltd. Amendments issued since publication Amd. No. Date of issue CommentsBS4639:1987 BSI 08-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Definitions 1 3 Braking requirements for towed agricultural vehicles 2
6、 4 Braking requirements for agricultural towing vehicles 2 5 Characteristics and performance of complete braking systems 2 6 Tests and test report 3 Appendix A General conditions for tests 4 Appendix B Method of testing the braking force of service brakes 4 Appendix C Method of testing the resistanc
7、e to gravity of parking brakes 5 Appendix D Specimen test report 6 Publications referred to Inside back coverBS4639:1987 ii BSI 08-1999 Foreword This revision of this British Standard, which has been prepared under the direction of the Agricultural Machinery and implements Standards Committee, super
8、sedes BS4639:1970 which is withdrawn. It maintains the same primary objective of the earlier edition, which is to improve the safety of operation of agricultural vehicles both on and off the road. At the same time it is recognized that, bearing in mind the small proportion of their time spent on pub
9、lic roads and their low speed, they do not require the same braking performance as normal road vehicles. The overall aim of achieving a deceleration of2.5m/s 2with all vehicles and combinations of vehicles is, therefore, maintained. Since1970 the most significant development nationally in this field
10、 has been the publication by the Department of Transport of a code on agricultural trailer braking systems. This code complements the Motor Vehicles(Construction and Use) Regulations,1978, as amended by Statutory Instrument1984, number1809. It recommends the use of a single line hydraulic system for
11、 actuation on the majority of vehicles so as to achieve maximum interchangeability and safety. Other methods of brake actuation are, however, not excluded. Internationally work on harmonization of legislation within the United Nations Economic and Social Council Economic Commission for Europe(ECE) h
12、as continued, and on development of test procedures within the International Organization for Standardization(ISO). Test methods in this standard are technically equivalent to ISO5697:1982 “Agricultural and forestry vehicles Determination of braking performance” published by ISO. As far as possible
13、every effort has been made to make this British Standard compatible with existing and proposed regulations and recommendations, both national and international. The definitions in this standard are based on the Motor Vehicles(Construction and Use) Regulations,1978, as amended by Statutory Instrument
14、1984, number1809. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This d
15、ocument comprises a front cover, an inside front cover, pagesi andii, pages1 to8, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS4639:1987 B
16、SI 08-1999 1 1 Scope This British Standard specifies requirements for the brakes and braking systems of towed agricultural vehicles in combination with agricultural towing vehicles (normally agricultural tractors). It contains braking requirements for the towed vehicle and for the towing vehicle to
17、ensure their compatibility and requirements for the characteristics and performance of the complete braking system. Conditions of test are given in Appendix A and tests for service brakes and parking brakes are given in Appendix B and Appendix C respectively. A specimen test report is given in Appen
18、dix D. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 2 Definitions For the purposes of this British Standard the following definitions apply. 2.1 towed agricultural vehicle an agricultural trailer, the main purpose of which is to carry agricultu
19、ral produce, or any towed agricultural vehicle having a maximum weight exceeding twice its unladen weight but not being an agricultural trailed appliance conveyor 2.2 agricultural trailed appliance conveyor a trailer having an unladen mass not exceeding510kg which is designed and constructed for the
20、 conveyance of not more than one agricultural trailed appliance and which has each of its wheels fitted with a pneumatic tyre 2.3 agricultural trailed appliance a trailed implement or machine constructed or adapted for use off roads for agricultural, horticultural, or forestry purposes and having a
21、maximum weight not exceeding twice its unladen weight 2.4 balanced vehicle a towed agricultural vehicle generally having two or more axles so that the weight of the vehicle is supported by its road wheels when the vehicle is detached from the towing vehicle 2.5 unbalanced vehicle a towed agricultura
22、l vehicle, so constructed that part of the weight of the vehicle is not supported by the road wheels when the vehicle is detached from the towing vehicle, e.g.having one axle, or two axles if closely spaced 2.6 brake control that part of the braking system which is directly actuated by the driver 2.
23、7 inertia(over-run) brake a service brake actuated by a compressive force in the hitch between towed and towing vehicles 2.8 service brake that brake normally applied by the driver to decelerate a moving vehicle 2.9 unladen weight the weight of the unladen vehicle 2.10 maximum weight those maximum a
24、xle and gross weights stated by the manufacturer to be technically permissible NOTEThese weights may be greater than the “maximum weights” authorized by the national administration. 2.11 maximum mass the mass corresponding to the maximum weight 2.12 unladen vehicle a vehicle in running order with, w
25、here appropriate, its tanks and radiators full and carrying only a driver of mass75kg, but no optional accessories or load, where these are applicable 2.13 independent braking the braking of the towing and towed vehicles by separate independent controls operated by the driver in the driving position
26、 of the towing vehicle 2.14 simultaneous braking the braking of the towing vehicle and the towed vehicle by a single control operated by the driver in the driving position of the towing vehicle and where the muscular energy of the driver is not the energy used for braking the towed vehicleBS4639:198
27、7 2 BSI 08-1999 2.15 Axle 2.15.1 two stub axles which are fitted on opposite sides of the longitudinal axis of the vehicle 2.15.2 any axle other than a single stub axle, whatever type or number are fitted to the vehicle 3 Braking requirements for towed agricultural vehicles 3.1 Service brakes 3.1.1
28、Towed agricultural vehicles shall be fitted with the following types of braking systems, according to their maximum masses. Where an over-run device is the only means of operating the brakes the maximum mass of the vehicle shall not exceed3500kg. 3.1.2 Every towed agricultural vehicle which is requi
29、red to be fitted with a service brake shall have braking devices which act on at least half of the vehicles wheels. These braking devices shall act on all the wheels of at least one axle and the action of these brakes shall be symmetrically distributed between the wheels in relation to the median lo
30、ngitudinal plane. An effective means of adjustment shall be fitted so that the brakes can be easily adjusted and be compensated for any wear. 3.1.3 The service brake of a towed agricultural vehicle shall be capable of achieving a braking force equal to at least25% of the maximum weight of the vehicl
31、e. 3.1.4 Braking systems on towed agricultural vehicles employing fluid transmissions shall be capable of accommodating a maximum nominal pressure of150bar 1)for hydraulic systems and8bar for pneumatic systems. 3.1.5 Braking systems on towed agricultural vehicles employing fluid transmissions shall
32、not operate when the pressure is less than5bar in hydraulic systems, or0.5bar in pneumatic systems. 3.2 Parking brakes. All towed agricultural vehicles required to have a service brake shall be fitted with a parking brake complying with5.2. 4 Braking requirements for agricultural towing vehicles NOT
33、EIf an agricultural towing vehicle is equipped with a towing device, the preferred system of braking for actuating the service brakes of towed agricultural vehicles is hydraulic. Other braking systems, for example pneumatic, may be fitted where appropriate. 4.1 Hydraulic braking systems for actuatin
34、g the service brakes of towed agricultural vehicles shall be of the single line type. 4.2 It shall be possible to increase the towed vehicle service brake line pressure progressively by operation of the towing vehicle brake control device from zero for hydraulic systems or1bar for pneumatic to the m
35、aximum. This maximum shall be not less than120bar and not more than150bar for hydraulic systems or not less than6.5bar and not more than8bar for pneumatic systems. 4.3 The towed vehicle braking system shall be such that the energy source cannot be inadvertently disconnected from the engine of the to
36、wing vehicle. 4.4 The braking system shall be capable of accommodating the maximum fluid pressure likely to be imposed on it. 4.5 The service brake control for applying the brakes of the towed agricultural vehicle shall be capable of being operated over its full range by the driver from the driving
37、position, whilst retaining steering control of the moving vehicle. 4.6 The brake control shall be of the simultaneous and/or independent type. 5 Characteristics and performance of complete braking systems 5.1 Service brakes NOTEThe preferred system of braking is hydraulic. Other braking systems, for
38、 example pneumatic or over-run, may, however, be used where appropriate. 5.1.1 Hydraulic braking systems shall use a single hydraulic connection between the towing and towed vehicles. 5.1.2 The male component of a hydraulic coupling shall be attached to the towing vehicle. For pneumatic systems the
39、male component of the control(service) line and the female component of the supply(emergency) line shall be attached to the towing vehicle. 5.1.3 The coupling shall comply in all respects with the requirements contained in ISO5676 for hydraulic systems and BS AU138a for pneumatic systems. Not exceed
40、ing0.75t: no brakes required; 0.75t to3t: any type of braking system; 3t to8t: over-run, independent or simultaneous braking; More than8t: simultaneous braking. 1) 1bar=10 5 N/m 2 =100kPaBS4639:1987 BSI 08-1999 3 5.1.4 Hydraulic braking systems shall be tolerant of high quality solvent refined paraf
41、fin mineral oils containing balanced additions, and any other transmission oils which are regularly used for the machinery of agricultural engineering. 5.1.5 In the case of simultaneous braking, with a fluid pressure at the coupling of100bar for hydraulic systems or6.5bar for pneumatic systems, a br
42、aking force equal to at least25% of the maximum weight of the vehicle shall be achieved, when tested in accordance with Appendix B, on both towing and towed vehicles, with pedal or hand lever forces not exceeding600N or400N respectively. NOTEThe preferred maximum pedal or hand lever forces are450N o
43、r250N respectively. 5.1.6 In the case of independent braking, with a fluid pressure at the coupling of100bar for hydraulic systems or6.5bar for pneumatic systems, a braking force equal to at least25% of the maximum weight of the vehicle shall be achieved, when tested in accordance with Appendix B, o
44、n the towed vehicle, with pedal or hand lever forces not exceeding600N or400N respectively. NOTEThe preferred maximum pedal or hand lever forces are450N or250N respectively. 5.1.7 In the case of an over-run brake a braking force on the towed vehicle equal to at least25% of the maximum weight to be b
45、orne by its wheels shall be achieved, when tested in accordance with Appendix B, with an input force of not more than6% of the maximum weight to be borne by its wheels. The brakes shall not operate when the input force is less than2% of the maximum weight to be borne by its wheels. 5.1.8 The vehicle
46、 combination shall not significantly deviate from its course when any or all of the service brakes are applied. 5.2 Parking brakes. A towed agricultural vehicle fitted with a parking brake shall be such that it will be held stationary, when tested in accordance with Appendix C, with pedal or hand le
47、ver forces not exceeding600N or400N respectively, on an18% up or down gradient, when loaded to its maximum weight and disconnected from the towing vehicle. NOTEThe preferred maximum pedal or hand lever forces are450N or250N respectively. 6 Tests and test report 6.1 Tests shall be carried out in acco
48、rdance with the general conditions given in Appendix A. 6.2 A test report shall be provided by the manufacturer in a form such as that given in Appendix D.BS4639:1987 4 BSI 08-1999 Appendix A General conditions for tests A.1 The towed agricultural vehicle shall be coupled to a towing vehicle with wh
49、ich it is recommended for use by the manufacturer. A.2 The towed agricultural vehicle shall be laden to its maximum weight with any unbraked axle laden to its maximum weight. If the vehicle is a balanced vehicle and all wheels are braked, the front axle shall be laden to its maximum weight. If the vehicle is an unbalanced vehicle, the maximum design transferred weight shall be carried on the towing vehicle. A.3 The test track or test site shall have a dry, clean concrete, bituminous or an equivalent surface affording good adhesion. A.4 For the service brake test and gravity
